Rotary drill bit and stabilizer



ROTARY DRILL BIT AND STABILIZER Archer W. Kammerer, Jr., Fullerton, Calif., assignor to Archer W. Kammerer, Fullerton, Calif.

The present invention relates to rotary drill bits or stabilizers useful in well bores.

An object of the present invention is to provide a rotary drill bit or stabilizer possessing blades or cutters removably mounted on the main body of the tool, the blades or cutters being replaceable on the body with facility.

Another object of the invention is to provide a rotary drill bit or stabilizer, in which the effective size of the tool can be changed very readily merely by mounting diiferent size blades on the main body of the tool.

A further object of the invention is to provide a rotary drill bit or stabilizer having blades that are easy to assembio and disassemble with respect to the main body of the tool, the tool being economical to manufacture and maintain, and possessing strong and sturdy characteristics.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings: I

Figure 1 is a longitudinal section through the lower portion of a drill bit or stabilizer embodying the invention, taken along the line 11 on Fig. 2;

Fig. 2 is a cross-section taken along the line 2-2 on Fig. 1;

Fig. 3 is a cross-section, on an enlarged scale, taken along the line 3-3 on Fig. 1.

As disclosed in the drawing, a drill bit or stabilizer A is provided which is adapted to drill or ream a well bore B, or which is to stabilize a rotary drill bit or the drill string itself (not shown) in the well bore.

T he tool A includes a main body 16, the upper portion of which (not shown) is adapted to be connected to a string of drill pipe or the like extending to the top of the well bore, and by means of which the apparatus is rotatable in the well bore while drilling fluid is being pumped downwardly through the drill pipe and the body of the tool. Such drilling fluid will pass downwardly through a central fluid passage 11 in the body, exiting from the lower portion of the body and then returning through the annulus around the drill pipe to the top of the hole.

The lower portion of the main body is provided with circumferentialiy spaced longitudinal grooves 12, each of which terminates in an upper, downwardly facing transverse body shoulder 13. Each groove opens downwardly through the lower end 14 of the body. Each groove also includes a relatively wide inner portion 15 communicating with the periphery of the body through a substantially narrower central portion 16 to form opposed longitudinal body ribs 17. A cutter and pilot blade 18, or a stabilizing element, is inserted upwardly into each groove 12. Each blade includes opposed longitudinally atent ,enlarged bore portion 30.

at which its operation is to commence.

"ice

portion 23 of each blade is curved in a downward and inward direction to form a guide, such curved portions merging into a bottom hole engaging portion 24 extending inwardly across the bottom of the body 10. As stated above, each blade 18 is inserted into the body until its upper end engages the downwardly facing body shoulder 13, at which time a tapered inner surface 25 on each blade will engage the companion tapered surface 14 at the lower end of the body.

Once the blades 18 are moved upwardly into the 'body grooves 12 into engagement with the upper bodyshoulders 13 and with the lower tapered inner surface 14, they are each retained in such position by a holding screw 26. This holding screw has a threaded shank 27 .received within a lateral threaded bore 28 in the body, the head 29 of the screw being slidable within an enlarged diameter bore portion 30 disposed inwardly of the longitudinal body groove 12. Before a Cutter blade 18 is moved upwardly into the body, the screw 26 is threaded inwardly of the lateral bore 23 to its fullest extent, in which the outer end of the head is disposed laterally inward of the longitudinal groove 12, in order to avoid interference with upward sliding of the blade 18 within the body groove. When a blade is disposed in engagement with the body shoulder 13 and the lower tapered inner surface 14, a suitable tool, such as a screw driver (not shown), is inserted through a lateral hole 31 in the blade in alignment with a non-circular opening 32 in the screw head 29, the screw being rotated in an unthreading direction to feed it laterally outward to locate its head in a transverse groove 33 formed in the inner portion of the cutter blade 18. The longitudinal extent of the groove 33 is only slightly greater than the diameter of the head 29 to prevent the blade 18 from having any substantial movement lengthwise of the body 10.

If it is desired to prevent inadvertent return threading of the screw 26 in the lateral bore 28, a retainer device in the form of a helical spring 34 may be located in the This spring bears against a shoulder 35 at the inner end of the enlarged bore portion and also against the head 29 of the screw. However,

- the spring 34 need'not be used, but its use is preferred as a precautionary measure.

In the use of the apparatus, it is lowered in the well bore B by means of the string of dril pipe to the location The drill pipe and the tool itself are then rotated at the proper speed, the blades 18 engaging the wall of the well bore to stabilize the drilling string in the latter. Preferably, the outer surfaces of the blades 18 are hardfaced to increase their life. In the event that the apparatus is to be used for drilling purposes, it can operate upon the bottom portion of the well bore B, its lower curved elements 23 engaging bottom and tending to center the tool in the well bore. The string of drill pipe and the tool are rotated at the proper speed, with the blades engaging the wall of the formation while the proper drilling weight is imposed on the tool. Any downward forces imposed by the body 10 on the drilling blades 18 are transmitted directly to the latter from the downwardly facing shoulders 13 to the upper ends of the blades, as well as from the lower tapered inner surfaces 14 to the companion tapered surfaces 25 of the blades.

Rotary motion is -t'ransrriitted from the body 10 directly to'the blades 18 by virtue of the flange or rib 19, 17 and groove 15, 20 interconnection between the parts, which preferably make a snug sliding fit. Such rotary motion is not transferred at all through the retaining screws 26, since theblades will engage the upper and lower shoulders or surfaces 13, 25 without the lower or upper sides of transversegrooves 33 engaging theheads 29 of the screws. Actually, each screw 26 is primarily useful in preventing an associated blade 18 from dropping downwardly-with respect to the body 10. During the drilling operation in the well bore, the upper and lower body shoulders 13,

14 engage the blades 18 to maintain the proper assembled relation between the body and the blades, even if the holding screws 26 were absent.

In the event the blades 18 become worn, the tool need merely be elevated to the top of the well bore, and the screws 26 threaded inwardly of the transverse bores 28 to their fullest extent, which then allows the blades to be slipped downwardly out of the grooves 12 and a new set of blades inserted in their place, whereupon the screws 26 may again be unthreaded within the bores 26 to locate their heads 29 in the transverse grooves 33 to retain the blades in the proper assembled relation to the body.

Not only are the blades 13 easily replaceable, but the construction of the tool permits different size blades to be mounted on the body. The inner portions of the blades would all be alike. However, the effective drilling diameter or stabilizer diameter of the tool can be changed merely by substituting sets of blades that extend radially outward of the body by different amounts.

Accordingly, it is evident that a tool has been provided which is capable of functioning as a rotary drill bit, rotary stabilizer, or as both. The blades 18 are readily assembled and disassembled with respect to the body 10. In addition, the effective size of the tool can be changed merely by changing the dimensions of the blades, as by substituting blades that project outwardly of the body to different radial extents. The tool is of strong and sturdy construction, the drilling weight being transmitted from the body 10 directly to the blades 18, while a large area of the body is in contact with the blades to transmit drilling torque therebetween in a safe manner.

The inventor claims:

1. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal grooves therein terminating in a downwardly facing body shoulder; blades'disposed in said grooves in engagement with said shoulder and projecting laterally outward of said body; and laterally shiftable retaining means secured to said body inwardly of said blades and movable laterally outward into engagement with inner portions of said blades 'to hold said blades in said body grooves.

2. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal grooves therein terminating in a downwardly facing body shoulder; said grooves opening through the lower portion of said body; blades disposed in said grooves in engagement with said shoulder and projecting laterally outward of said body, said blades being removable in a downward direction from said grooves through the lower portion of said body; and laterally shiftable retaining means secured to said body inwardly of said blades and movable laterally outward into engagement with inner portions of said blades to prevent substantial downward movement of said blades away from engagement with said shoulders.

3. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentialiy spaced longitudinal grooves terminating at upper downwardly facing body shoulders "and'at lower downwardly facing tapered surfaces; said grooves opening through said lower surfaces; blades disposed in'said grooves and projectinglateraliy outward'of -3 said body, said blades engaging said shoulders and having tapered surfaces companion to and engaging said downwardly facing tapered surfaces, said blades being removable in a downward direction from said grooves through the lower ends of said grooves; and retaining means secured to said body inwardly of said blades engageable with inner portions of said blades to prevent substantial downward movement of said blades away from engagement with said shoulders and tapered surfaces.

4. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal grooves terminating at downwardly facing body shoulders, the inner portion of each groove being wider than its outer portion which opens through the periphery of said body;

said body having longitudinal ribs adjacent said grooves;

blades disposed in said grooves in engagement with said shoulders and projecting laterally outward of said body. each blade including longitudinally extending flanges in the inner portion of each groove and having longitudinal grooves outwardly of said flanges receiving said longitudinal body ribs; and laterally shiftable retaining means secured to said body inwardly of said blades and movable laterally outward into engagement with inner portions of said blades to hold said blades in said body grooves.

5. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal grooves therein terminating at upper downwardly facing body shoulders and at lower downwardly facing tapered surfaces, said grooves opening through said lower surfaces; the inner portion of each groove being wider than its outer portion which opens through the periphery of said body; blades disposed in said grooves and projecting laterally outward of said body, said blades engaging said shoulders and having tapered surfaces companion to and engaging said downwardly facing tapered surfaces, said blades being removable in a downward direction from said grooves through the lower ends of said grooves; each blade including longitudinally extending flanges in the inner portion of each groove and having longitudinal grooves outwardly of said flanges receiving longitudinal body ribs; and retaining means secured to said body inwardly of said blades and engageable with inner portions of said blades to prevent substantial downward movement of said blades away from engagement with said shoulders and tapered surfaces.

6. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal grooves therein terminating in a downwardly facing body shoulder; blades disposed in said grooves in engagement with said shoulder and projecting laterally outward of said body; each blade having an inner recess; said body having a threaded bore in alignment with each of said recesses; and a screw threaded in each bore and adapted to be disposed in a recess to hold each blade in its groove.

7. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal grooves therein terminating in a downwardly facing body 'shoul-' der; blades disposed in said grooves in engagement with said shoulder and projecting laterally outward of said body; each blade having an inner recess; said body having a threaded bore in alignment with each of said recesses; a screw threaded in each bore and adapted to be disposed in a recess to hold each blade in its groove; and spring means engaging said body and each screw to resist rotation of said screw in the threaded bore.

8. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal 'grooves therein terminating in a downwardly facing body'shoulder; blades disposed in said grooves in engagement with said shoulder and projecting laterally outward of said body; each blade having an inner recess; said body having a threaded bore in alignment with each of said recesses; a screw threaded in each bore and adapted to be disposed in a recess to hold each blade in its groove; each blade having a lateral hole opening through its outward surface and through which a tool is insertable to rotate each screw to move each screw selectively into or out of the recess aligned therewith.

9. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal grooves therein terminating at upper downwardly facing body shoulders and at lower downwardly facing tapered surfaces, said grooves opening through said lower surfaces; the inner portion of each groove being wider than its outer portion which opens through the periphery of said body; said body having longitudinal ribs adjacent said grooves; blades disposed in said grooves in engagement with said shoulders and tapered surfaces and projecting laterally outward of said body, said blades being removable in a downward direction from said grooves through the lower ends of said grooves; each blade including longitudinally extending flanges in the inner portion of each groove and having longitudinal grooves outwardly of said flanges receiving said longitudinal body ribs; each blade having an inner recess; said body having a threaded bore in alignment with each of said recesses; and a screw threaded in each bore and adapted to be disposed in a recess to hold each blade in its groove.

10. In apparatus useful in the performance of a rotary drilling operation in a well bore: a main body having a plurality of circumferentially spaced longitudinal grooves therein terminating at upper downwardly facing body shoulders and at lower downwardly facing tapered surfaces, said grooves opening through said lower surfaces; the inner portion of each groove being wider than its outer portion which opens through the periphery of said body; said body having longitudinal ribs adjacent said grooves; blades disposed in said grooves in engagement with said shoulders and tapered surfaces and projecting laterally outward of said body, said blades being removable in a downward direction from said grooves through the lower ends of said grooves; each blade including longitudinally extending flanges in the inner portion of each groove and having longitudinal grooves outwardly of said flanges receiving said longitudinal body ribs; each blade having an inner recess; said body having a threaded bore in alignment with each of said recesses; a screw threaded in each bore and adapted to be disposed in a recess to hold each blade in its groove; each blade having a lateral hole opening through its outward surface and through which a tool is insertable to rotate each screw to move each screw selectively into or out of the recess aligned therewith; and spring means engaging said body and each screw to resist rotation of each screw in the threaded bore.

References Cited in the file of this patent UNITED STATES PATENTS 1,510,871 Swaim Oct. 7, 1924 1,526,677 Painter Feb. 17, 1925 1,703,390 Duffy Feb. 26, 1829 2,095,852 Booth Oct. 12, 1937 

